A new review of studies from around the world shows that where girls lag behind boys in math (and it's not everywhere), the cause is likely culture, not biology.

Inspired in part by Larry Summers's comment that "issues of intrinsic aptitude" were behind the gender gap in math performance, Professors Janet Hyde and Janet Mertz of the University of Wisconsin-Madison decided to review the available evidence and see if boys consistently outperformed girls at the highest levels. Summers's claim — and one accepted by many others — was that while girls might perform as well as boys on average, boys had a greater variability of mathematical aptitude and thus might always dominate in the upper echelons of mathematics. No woman, some note, has ever won the Fields Medal, math's most prestigious honor. But Hyde and Mertz found that the gap between boys and girls at the top levels of achievement did *not* persist throughout the world, and was smaller in countries with greater gender equality.

In Iceland, Thailand, and the UK, 15-year-old girls outnumbered boys at the top levels of math achievement. In most countries studied, girls' math skills were just as variable as boys', and in the Netherlands they were actually more variable. In general, countries where girls matched or outperformed boys were also countries with high gender equality — like Denmark, Iceland, in the UK. All of these are in the top twelve — the US is 31, right before Kazakhstan. This suggests that culture, not biology, is holding girls back in countries where boys still outperform them.

Hyde and Mertz found that the gender gap in math doesn't even hold across all ethnic groups in the US. For Asian-Americans, more girls than boys scored in the top 1% in one battery of tests. Essentially, Summers's claim of greater variability seemed only to apply to white American kids. Mertz says, "U.S. culture instills in students the belief that math talent is innate; if one is not naturally good at math, there is little one can do to become good at it. In some other countries, people more highly value mathematics and view math performance as being largely related to effort."

It's no surprise that in a country where math skill is assumed to be innate, and where prominent people tell girls they have less innate skill, that girls might not always measure up to boys. We know that negative stereotypes can affect performance, but even in the face of people like Summers, girls in the US are catching up to boys. Girls now take high school calculus at the same rate as boys, and 30% of math doctorates go to women now, as opposed to 5% in the 1950s. American girls may have a ways to go before they reach total equality, but it's going to take more than Larry Summers to keep them down.

Girls Worse At Math? No Way, New Analysis Shows [Reuters]

Culture, Not Biology, Underpins Math Gender Gap [EurekAlert]

Girls Get Math: It's Culture That's Skewed [LiveScience]

Gender Gap In Maths Driven By Social Factors, Not Biological Differences [ScienceBlogs]

Gender Stereotypes Can Affect Men's And Women's Test Performance in Math, Study Shows [NYU]

The Global Gender Gap Report 2007 [World Economic Forum]